Restore fix undone by https://github.com/grpc/grpc/pull/5893

That PR wasn’t tested nor reviewed adequately.

Support dynamic frameworks

This fixes Jenkins for that branch, as a backwards-incompatible change
was made in the script that runs the tests for all branches.

The lines added are exactly the same as those now in master, so that the
subsequent merge of 0.14 into master doesn’t conflict.

Now that the submodule points to 3.0.0-beta-3.1, which is what we need.

That PR wasn’t tested nor reviewed adecuately.

Apple hasn’t created a module map for that system header, which means
it can’t be used from frameworks.

Cocoapods 1.0 keeps the directory structure of the public headers when
creating a dynamic framework, so if we keep the header_mappings_dir as it
was, includes would need to be of the form #include <openssl/openssl/ssl.h>

This means our header_mappings_dir has to be ‘include/openssl’ instead of
‘include’. Which in turn means that, for static libraries, we have to tell
Cocoapods to prepend an ‘openssl’ directory to the headers. We do that
with the ‘header_dir’ attribute of the podspec.

Move tests to Cocoapods 1.0.0

And print version before and after install, so we can always check.

PHP: update package.xml after fixes

Backport C# changes to 0.14 branch

Updated functions with TSRM macros for ZTS support

Update third_party/protobuf to v3.0.0-beta3 (in  release-0_14  branch)